I understand from an existing question that a fall does not trigger an Opportunity Attack, but what happens if the player purposefully initiates the "fall", e.g. the character flies to a position three squares above and one to the side of a target medium-sized creature, and then lets themself "fall", rather than move, so they land in the square adjacent to the target without triggering an OA.

Is this a good hack of the system to avoid OA?

The example is a Monk with the Swift Flight power ...

Effect: You fly a number of squares equal to your speed + your Wisdom modifier. If you don’t land at the end of this movement, you fall.

and a Safewing Amulet ...

Property When falling, you reduce the distance fallen (for the purpose of calculating damage) by a number of feet equal to 10 × the amulet’s enhancement bonus. You always land on your feet after a fall.

From the Rules Compendium, p209

No Opportunity Actions Triggered:

When a creature falls past an enemy, the creature does not trigger opportunity actions, such as opportunity attacks, from that enemy that are triggered by movement."

3 Answers
3

As the rule you cited points out, you do not provoke OAs when falling. The trick is making sure that you're actually falling when you cover those last couple squares, rather than descending in some other manner.

Case 1: Any Flight with Explicit Falling

Different methods of gaining flight act differently. Some powers that let you fly or items that give you a flight speed explicitly say that you fall at the end of the movement if you don't end on solid ground, so obviously you can fly to the point above where you want to be then end the movement, and you'll fall.

Example: Airstriders (level 25 foot item from Adventurer's Vault)

Property: You take no damage from a fall and always land on your feet. You have a fly speed equal to your speed +2, but you must end each turn on a solid surface or you fall.

On a side note, remember that when you fall you end up prone and take 1d10 damage per 10 feet you fell (minus any damage you avoid through a trained acrobatics check) unless you have a way of avoiding these penalties (such as the aforementioned Airstriders), which may not always be better than provoking an OA.

Verdict: Does not trigger OAs.

(Thanks wax eagle for pointing out you have to be trained in acrobatics!)

Case 2: Flight Speed with Deliberate Crashing

If you've gained an actual flight speed somehow (such as Zephyr Boots, from Adventurer's Vault 1) then you can move to a point above where you want to be then drop prone as a minor action, which will cause you to crash.

DMG pg47, on Flying:

Knocked Prone: A flying creature that is knocked prone crashes.

However...

DMG pg48, on Crashing:

Safe Distance: A flying creature that crashes immediately drops a distance equal to its fly speed. If it reaches the ground, it lands safely.

You only start actually falling after this safe descent phase, and since this safe descent appears to count as flight, it provokes OAs as normal. This means that you can use falling to avoid OAs, but the point you crash from must be at least your speed above the spot where you want to start avoiding OAs, which means you'll need at least 1 round to get into position.

Verdict: Does not trigger OAs if you start the crash from high enough up.

Case 3: "Powered" Flight with Safe Landing

The problem is that most powers that let you fly a short distance say that you descend safely if you end the flight not on a safe surface. As with the crashing rules, this safe descent is not falling, and doesn't appear to contain any exemption from OAs. Thus, while falling is in fact a valid way to avoid OAs, not all powers that grant flight will allow you to fall.

Example: Windwalker (Genasi Windsoul racial power)

Effect: Fly 8 squares. If you don't end your move on solid ground, you float to the ground without taking falling damage.

But OAs are triggered on LEAVING a threatened square. So if you fall to the ground in front of someone, the opp you trigger is from leaving the square five feet above the ground (before you know if you're falling to their feet or not). Suppose I was standing in front of a trap door that has a fifty percent chance of breaking open when a creature lands on it. When a creature triggers the OA from the square ahead and above me (the only opp it would trigger before hitting the trap door), do I get an opp?
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AceCalhoonJun 1 '12 at 14:08

@AceCalhoon if your opponent goes through the trap door then he fell past you hence no AoO. If your opponent does not trigger the trap door then he did not go past you hence you do get an AoO.
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briddumsJun 1 '12 at 19:21

1

@SteveC A falling opponent would trigger when he went from the square that is above the square he landed on (assuming a direct downwards motion). Remember that when dealing with 3D combat you threaten 26 square: the 8 around you, 9 above you and 9 below you.
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briddumsJun 1 '12 at 19:24

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@Briddums At the time the AoO is triggered (on leaving the square above ground level), the trap door has not been encountered yet. There is no way to know whether or not it will trigger, because the falling character hasn't hit it yet.
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AceCalhoonJun 1 '12 at 19:29

In your suggested example, falling is useless as it doesn't change anything.

You describe a way how the PC could arrive next to the monster by falling, thus 'avoiding' OA. However, simply walking up to the same spot would also work - it wouldn't provoke OA, since only leaving the threatened square provokes opportunity attack.

Flight would allow you to flank the enemy by not going around him, but over him - but falling isn't needed since you don't provoke OA by arriving next to the enemy (unless it has threatening reach).

Falling would allow you to leave the enemy without OA if you're standing on a conveniently located trapdoor, but again, that isn't the intended use case.

If the PC is in one of the 8 squares surrounding the enemy 3 squares above, exiting the layer directly above the enemy to the one ground level adjacent provokes. This would be the same as walking from one square adjacent to an enemy to another similarly adjacent.
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wax eagle♦Feb 23 '14 at 2:26

IF the PC would move in exactly that path then yes, but come on - when flying, you can easily arrive there in a curved path that doesn't go through any of the squares (cubes?) directly above the enemy, especially since you can also move diagonally in all 3 dimensions. Just as if you'd walk around the monster in order to flank, but with the difference that his buddies next to him won't block you from walking around.
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PeterisFeb 23 '14 at 7:31